Bottom Line:
The steady-state solar-induced Chl fluorescence yield ratio correlated very well with the artificial-light-induced one (R(2) = 0.84).A new methodology is then presented to estimate photochemical yield of photosystem II (ΦPSII) from the SIF measurements, which was verified against the standard Chl fluorescence measurement method (pulse-amplitude modulated method).The high coefficient of determination (R(2) = 0.74) between the ΦPSII of the two methods shows that photosynthesis process parameters can be successfully estimated using the presented methodology.

Mentions:
Figure 5 shows the relationships between leaf Chl content and steady-state Chl fluorescence yield ratios calculated from Figs. 3 and 4. Under artificial light, the ratio of ΦFa686.4/ΦFa760.5 showed a very clearly inverse curvilinear relationship with the Chl content of leaves (Fig. 5A; R2 = 0.94). A similar highly inverse curvilinear relationship was also obtained under solar light (Fig. 5B; R2 = 0.73) regardless of the large variation shown in Fig. 4. The lower coefficient of determination value obtained for the solar light-induced yield ratio is caused by wider variation at all Chl content values. A comparison of root mean square error (RMSE) values as indicated on the figure shows a much larger RMSE for the SIF method. However, when RMSEs are calculated for Chl content values below 400mg m−2, the RMSEs of the two methods become closer and amount to a maximum of 40mg m−2 for the SIF method, indicating that the SIF method might be less accurate for higher Chl content (above 400mg m−2) estimation.

Mentions:
Figure 5 shows the relationships between leaf Chl content and steady-state Chl fluorescence yield ratios calculated from Figs. 3 and 4. Under artificial light, the ratio of ΦFa686.4/ΦFa760.5 showed a very clearly inverse curvilinear relationship with the Chl content of leaves (Fig. 5A; R2 = 0.94). A similar highly inverse curvilinear relationship was also obtained under solar light (Fig. 5B; R2 = 0.73) regardless of the large variation shown in Fig. 4. The lower coefficient of determination value obtained for the solar light-induced yield ratio is caused by wider variation at all Chl content values. A comparison of root mean square error (RMSE) values as indicated on the figure shows a much larger RMSE for the SIF method. However, when RMSEs are calculated for Chl content values below 400mg m−2, the RMSEs of the two methods become closer and amount to a maximum of 40mg m−2 for the SIF method, indicating that the SIF method might be less accurate for higher Chl content (above 400mg m−2) estimation.

Bottom Line:
The steady-state solar-induced Chl fluorescence yield ratio correlated very well with the artificial-light-induced one (R(2) = 0.84).A new methodology is then presented to estimate photochemical yield of photosystem II (ΦPSII) from the SIF measurements, which was verified against the standard Chl fluorescence measurement method (pulse-amplitude modulated method).The high coefficient of determination (R(2) = 0.74) between the ΦPSII of the two methods shows that photosynthesis process parameters can be successfully estimated using the presented methodology.